The present disclosure relates generally to fluid cartridges, and more particularly, to a fluid cartridge for a fluid supply system.
Inkjet printers often use replaceable fluid cartridges to supply ink and/or other fluids to a printing device to form an image on print media. Some fluid cartridges include two or more internal chambers configured to hold the ink, where the chambers are often separated by a wall having an air/ink exchange port formed therein. The air/ink exchange port provides air and/or ink communication between the chambers. The ink is selectively taken from one or more of the chambers and delivered to and ejected through nozzles of a printhead and then onto the print media. In some instances, however, fluid may continue to flow through the printhead even when the printhead is not actuated by the printer.
To prevent the free flow of ink during non-use of the printhead, a negative or back pressure is formed in the ink within the cartridge that overcomes the pressure at the printhead when the printhead is not in use. Thus, a vacuum is formed in the free ink chamber of the cartridge and holds the ink therein. The back pressure within the free ink chamber of the cartridge is generally maintained by capillary force and the flow of air and/or ink back and forth through the air/ink exchange port. Difficulties may arise, however, in maintaining the back pressure in the cartridge when additional, unintended air enters the air/ink exchange port from various leak regions that may form during construction of the fluid cartridge.
Further difficulties may arise from a lack of desirable back pressure. For example, if one cartridge fails to provide sufficient back pressure, the ink may drool out the nozzles onto the orifice plate, and then may be drawn up by back pressure of another color cartridge. This may result in undesirable color mixing.